神经肌亚体内肌纤维型的生后发育(英文)

Postnatal Development Of Histochemical Muscle Fibers in Neuromuscular Subvolumes of Rabbit

将生后 2天、2周、4周、8周、12周、16周、2 0周、2 4周的家兔胫骨前肌分成前、后亚体 ,分别得到腓得神经主要肌分支的支配 ,腓深神经分支的神经分布型式随年龄增长而递降。每个肌亚体组织化学特征经由乙酰胆碱碘溶液孵育后的运动终板而确定。肌纤维可分成 SO、FG、FOG和FO型。除外生后 2天龄之外 ,前、后亚体内 SO、FG、FOG肌纤维在生后 2周龄、4周龄、8周龄分别约占 30 %左右 ,生后 12周龄以后 ,在前亚体内的 SO型与 FOG型纤维比率下降和 FG型纤维升高要超过后亚体。全部肌纤维型在生后 2周龄、4周龄、8周龄、12周龄的每个肌亚体的深、中、浅部都是均匀性分布。然而 ,不同部位的肌纤维类型差别明显 ,深部以氧化型为主 ,而浅部则以糖酵解型为主。这种差别在生后 16、2 0、2 4周龄是最典型的。两个亚体生后发育期间的每条肌纤维毛细血管数 (NCF)表明 SO>FO>FOG>FG型纤维和毛细血管数与肌纤维横切面积比 (CCA)显示 FO>SO>FOG>FG型纤维 。

The mtibialis anterior of rabbits in postnatal 24,20,16,12,8,4,2 weeks and 2 days can be devided into an anterior and a posterior subvolumes are supplied by the primary branches of its muscle nerve. Innervation patterns of deep peroned nerve branch decrease with rising ages. The histochemical profile of each subvolume was determined from motor end plates after acetylthiocholine iodide incubation. Fibers were classified as slow twitch oxidative (SO),fast twitch glycolytic (FG), fast twitch oxidative glycolytic (FOG), and fast twitch oxidative (FO). The percentage of SO G FO three fibers types of both subvolumes was respectively about thirty percent at postnatal 2,4,8 week ages except postnatal 2 days. After 12 week ages, SO fibers and FOG fibers decreased gradually and FG fibers increased progressively in anterior subvolume than posterior subvolume. All fiber types in the deep, intermediate and superficial portions of each subvolume presented a aniform distribution with each other at postnatal 2,4,8,12 weeks. Nevertheless, there was a gradient in the type of fibers, ranging from more oxidative in the deep region to more glycolytic in the superficial region, this gradient being more pronounced in postnatal 16,20,24 weeks.The number of capillaries per fiber (NCF) of both subvolumes during postnatal developments showed that SO>FO>FOG>FG fibers and the number of capillaries in relation to the fiber cross sectional area (CCA) showed that FO>SO>FOG>FG fibers. This indicates that the greater demand for oxygen supply may be achieved by decreasing the size of the muscle fiber rather than by increasing the number of associated capillaries.